According to an article in Lux Magazine, “scientists have discovered that the pigment featured in several famous artworks becomes unstable under LED lights”. The article reports that scientists blame the spectrum of LED sources for the damage of the paintings, however it cites no sources. A quick Google search brought up at least five more articles also blaming LEDs for the deterioration of the yellow pigment in the paintings.
Thankfully, MondoArc published an article on January 16th 2013 titled, “Study wrongly implies LED to blame for van Gogh masterpiece damage“. What this article says very well is that some wavelengths of blue light or ultraviolet radiation can cause damage to certain materials, including artworks and paintings. Many light sources include varying amounts of short wavelengths (aka blue light) in their spectrum. To blame LEDs in particular is to sensationalize the results of the research.
After reading the published articles by the original research team:
it is clear that the team used a Solarbox 1500e system:
which offers “The sun you have always wanted: sunshine day and night for accelerated light stability and weathering tests.”
Using the Solarbox, paint samples were put into an accelerated damage protocol, which included varying UV and short wavelength exposure (240 ≤ λ ≤ 400 nm, 335 ≤ λ ≤ 525 nm, and 335 ≤ λ ≤ 525 nm) for 98 hours at a time (using a 175W xenon lamp). The results of the study showed that the shorter the wavelenths of the light source, the more extreme the damage to the yellow paints being tested.
Any museum with masterpieces on display must be careful of the amount and type of light exposure the works are exposed to. However, it would be difficult to find a better light source out there than LEDs, at this time. What the articles should be cautioning, is that any light exposure can damage the paintings, and museums must be very careful to limit overexposure, especially in the short wavelengths and UV.